Pressure Activated Valve for High Flow Rate and Pressure Venous Access Applications

ABSTRACT

A valve having a first housing including a first lumen extending therethrough and a first disk-facing surface, a second housing including a second lumen extending therethrough and a second disk-facing surface, where the second housing is coupled to the first housing so that the second disk-facing surface faces the first disk-facing surface. A flexible disk has at least a portion of an outer edge of the disk extending away from a plane of a central portion of the disk, the outer edge contacting the first disk-facing surface, the disk including a slit extending therethrough which, when acted upon by a fluid pressure of at least a threshold level opens to permit fluid flow between the first and second lumens and which, when acted upon by a fluid pressure less than the threshold level, prevents fluid flow between the first and second lumens.

BACKGROUND

Pressure activated safety valves may be incorporated into medicaldevices such as peripherally inserted central catheters (PICCs), ports,dialysis catheters and tunneled central catheters which provide longterm access to the vascular system. Pressure activated safety valvesgenerally include a slitted, flexible disk extending across a lumen. Theflexible disk is generally constructed so that, when subjected to athreshold fluid pressure, edges of the slit separate from one another topermit flow through the lumen. When the pressure applied to the diskdrops below the threshold level, the slit reseals to prevent leakagefrom or to the vascular access device. It would be desirable at times toemploy within these vascular access devices fluid pressures in excess ofthe pressures to which these known flexible membranes have beentraditionally exposed to with hand injections (e.g., when flushing anobstructed lumen, administering high-flow rate fluids, etc.).

SUMMARY OF THE INVENTION

The present invention is directed to a valve comprising a first housingincluding a first lumen extending therethrough and defining a firstdisk-facing surface and a second housing including a second lumenextending therethrough and defining a second disk-facing surface, thesecond housing being mated to the first housing so that the seconddisk-facing surface faces the first disk-facing surface in combinationwith a flexible disk gripped between gripping portions of the first andsecond disk-facing surfaces, the disk including a slit extendingtherethrough which, when acted upon by a fluid pressure of at least apredetermined threshold level opens to permit fluid flow between thefirst and second lumens and which, when acted upon by a fluid pressureless than the threshold level remains sealed preventing fluid flowbetween the first and second lumens.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a section view of a device, according to a first exemplaryembodiment of the present invention;

FIG. 2 shows an enlarged view of the device of FIG. 1;

FIG. 3 shows a cross-sectional side view of capture area of a device,according to a second exemplary embodiment of the present invention;

FIG. 4 shows a perspective view of a portion of a second housing of thedevice of FIG. 3, according to a further embodiment;

FIG. 5 shows a perspective view of a portion of the second housing ofthe device of FIG. 3, according to an alternate embodiment;

FIG. 6 shows a cross-sectional a side view of a capture area of adevice, according to a third embodiment of the present invention;

FIG. 7 shows a cross-sectional side view of a capture area of a device,according to a fourth embodiment of the present invention;

FIG. 8 shows a cross-sectional side view of a capture area of the deviceof FIG. 7, according to an alternative embodiment;

FIG. 9 shows a cross-sectional side view of a capture area of the deviceof FIG. 8, according to a further embodiment;

FIG. 10 shows a cross-sectional side view of a capture area of a device,according to a fifth embodiment of the present invention;

FIG. 11 shows a cross-sectional side view of a capture area of a device,according to a sixth embodiment of the present invention;

FIG. 12 shows a cross-sectional side view of a capture area of a device,according to a seventh embodiment of the present invention;

FIG. 13 shows a cross-sectional side view of a capture area of a device,according to an eighth embodiment of the present invention; and

FIG. 14 shows a cross-sectional side view of a capture area of a device,according to a ninth exemplary embodiment of the present invention.

DETAILED DESCRIPTION

The present invention may be further understood with reference to thefollowing description and the appended drawings, wherein like elementsare referred to with the same reference numerals. The present inventionrelates to apparatus for controlling fluid flow through medical devicesspecifically for sealing devices which remain in place in the body toprovide long term access to the vascular system. To improve theperformance of pressure activated safety valves, embodiments of thepresent invention include features for fixing a disk and tuning thevalve performance to withstand the increased pressures and flow ratesassociated with certain procedures.

As described in more detail below, exemplary embodiments of the presentinvention provide features for enhancing the performance of a pressureactivated valve including a feature fixing a slitted, flexible disk in adesired position, a relief well to accommodate portions of the flexibledisk moved out of the fixation area and a slit bias feature creating abias aiding in tuning the performance of the valve (e.g., to select athreshold activation pressure).

As shown in FIGS. 1 and 2, a device 100 according to a first exemplaryembodiment comprises a first housing 102 and a second housing 104coupled to one another to hold a disk 106 therebetween. The device 100may further comprise an additional capture component 108, such as ano-ring. As shown in FIG. 1, the first housing 102 may, for example, belocated at a proximal end 122 of the device 100 while the second housing104 may be located at a distal end 124 of the device 100. As shown inFIG. 2, the first housing 102 includes a lumen 110 extendingtherethrough and a disk-facing surface 112. The second housing 104includes a lumen 114 extending therethrough and a disk-facing surface116. It will be understood by those of skill in the art that the firsthousing 102 and the second housing 104 are brought together to hold adisk 106 therebetween such that a pressure activated slit in the disk ispositioned between the lumens 110, 114 to control fluid communicationtherebetween. A circumference of the disk-facing surface 112 of thefirst housing 102 and the disk-facing surface 116 of the second housingmay be substantially the same as a circumference of the disk 106 so thatthe first housing 102, the second housing 104 and the disk 106 aresubstantially aligned within the device 100.

The disk 106 may, if desired, operate as a bi-directional valve allowingfluid flow through the device 100 in either direction. Alternatively,the disk 106 may be structured or, one or both of the first and secondhousings 102, 104, respectively, may include a structure preventing thedisk 106 from deforming in one direction and opening to permit fluidflow through the valve in that direction. Thus, fluid flow would bepermitted only in the other direction. Fluid may be being administeredto the body via the device 100 when a fluid pressure applied to theproximal end 116 of the device 100 exceeds a threshold value at whichthe disk 106 deforms so that the slit of the disk 106 opens to permitfluid flow therethrough to the distal end 118 of the device 100. So longas the fluid pressure remains at least as great as the threshold level,the slit remains open and fluid passes through the disk 106 and thelumen 112 to the body. Fluid may be withdrawn from the body when anegative fluid pressure applied to the proximal end 116 exceeds thethreshold level deforming the disk 106 and the slit thereof proximallyto permit fluid flow from the distal end 118 of the device 100 to theproximal end 116 thereof. The fluid may be drawn from the body throughthe lumen 112 of the second housing 104. This fluid flow will bemaintained so long as the fluid pressure remains at least the thresholdvalue. As soon as the fluid pressure applied against the disk 106 ineither direction drops below the threshold level, the disk 106 returnsto the sealed configuration in which edges of the slit therethrough abutone another preventing fluid flow therethrough.

The disk 106 may be flexible such that the disk 106 may be held betweenthe first housing 102 and the second housing 104 in a substantiallyplanar configuration or in a deformed configuration, as shown in FIG. 2.The capture component 108, shown as an o-ring, may be housed between thefirst housing 102 and the second housing 104 such that when the disk 106is held between the disk-facing surface 112 and the disk-facing surface116, an outer edge 118 of the disk 106 is deformed so that an outer edge118 extends away from a plane of a central portion 120 of the disk 106into a relief well 120 formed around a circumference of the disk-facingsurface 112 of the first housing 102. If it is desired to have asubstantially neutral valve (i.e., a valve with substantially equalthreshold pressure levels regardless of the direction of flow), thedisk-facing surfaces 110 and 114, between which the disk 106 is fixed,may be formed substantially planar to hold the central portion 120 inplace without bending it in one direction or the other. It will beunderstood by those of skill in the art, however, that other factorssuch as diameter, may also affect the tuning of the valve. In addition,either or both of those portions of the disk-facing surfaces 110, 114contacting the disk 106 and forming fixation features of the first andsecond housings 102, 104, respectively, may be coated, textured, coveredor overmolded with a thermoplastic elastomer or thermoset plastic suchas silicone to enhance the coefficient of friction to aid in valve diskretention during high flow applications.

In another embodiment, the disk 106 may be non-planar. For example,rather than a planar surface as shown in FIG. 2, the disk 106 may have aconcave or convex shape. It will be understood by those of skill in theart, however, that the disk 106 may take a variety of other non-planarshapes and forms so long as the disk 106 may be fixed between the firsthousing 102 and the second housing 104. It will also be understood bythose of skill in the art that the disk 106 may include more than oneslit which may be pressure activated. Additionally, either of or both ofthe first and second housings 102, 104, respectively, may include morethan one lumen extending therethrough. With flow through each of theselumens controlled by separate slits or by one or more common slitsextending across multiple lumens.

The following alternate embodiments, shown in FIGS. 3-14, aresubstantially the same as the device 100 described above, but mayinclude alternate geometrical aspects forming the fixation feature, therelief well and the slit bias. For example, the first and secondhousings of the following embodiments align such that the lumen of thefirst housing is in fluid communication with the lumen of the secondhousing with a flexible disk secured therebetween so that a slit of thedisk is positioned between the lumens to control fluid flowtherebetween. Additionally, the figures show a capture area of thedevice in which the disk would be held such that the device is depictedvia surfaces of a distal portion of the first housing and a proximalportion of the second housing.

As shown in FIG. 3, a device 200, according to another embodiment of thepresent invention comprises a first housing 202 and a second housing 204for securing a disk (shown in broken lines) therebetween. The firsthousing 202 includes a lumen 206 extending therethrough and a surface208, which faces a disk received in the space between the first andsecond housings 202, 204, respectively. The surface 208 may besubstantially planar so that an entire area thereof contacts the disk.The second housing 204 includes a lumen 210 extending therethrough and asurface 212 facing the space in which the disk will be received. Thesurface 212 may further include at least one protrusion 214 forming afixation feature pressing against the surface 208 a portion of the diskabutting thereagainst. The protrusion 214 may be formed as an annularring encircling the lumen 210 radially within an outer circumference 216of the second housing 204 with a circumference greater than an innercircumference of a wall 218 of the lumen 210. The protrusion 214 beformed by a continuous ring on the disk-facing surface 208 or, in analternative embodiment, the protrusion 214 may be formed as a series ofprojections extending discontinuously around the lumen 210 (e.g., as aseries of arcs extending along a curve around the lumen 210. Forexample, as shown in FIG. 4, the non-continuous ring shape may be formedby a series of castellated teeth of the disk-facing surface 208 of thesecond housing 204. In another embodiment, as shown in FIG. 5, thenon-continuous protrusion 214 may be formed by a series of saw teeth.Such non-continuous geometries provide localized areas of grip on thedisk. It will be understood by those of skill in the art that theprotrusion 214 may be formed by any variety of geometrical shapes.

A space 220 radially outside the protrusion 214 (i.e., between theprotrusion 214 and the outer circumference 216) forms a relief well intowhich a radially outer portion of the flexible disk will extend,substantially unsecured and enabled to flex accommodating the vibrationsassociated with high pressure fluid flow through the slit. Additionally,a space 222 radially within the protrusion 214 would allow a centralportion of the disk, including the slitted portion, to flex toward thesecond housing 204, until the central portion of the disk contacts thesurface 212. Thus, the device 200 will be able to withstand increasedfluid pressures when fluid flows through the device in a positivedirection (from the first to the second housing). It will be understoodin the art, however, that the slit is not biased in any particulardirection when there is no fluid flow through the device 200. Thoseskilled in the art will also understand that the designation of thefirst housing 202 as upstream (i.e., proximal) of the second housing 204is exemplary only and may be reversed as may the location of theprotrusion 214. That is, the second housing 204 may be formed as eitherthe proximal or distal end of the valve of the device 200 and theprotrusion 214 may be formed on either of the first and second housings202, 204, respectively, in either the proximal or the distal of the two.

According to another embodiment of the present invention, as shown inFIG. 6, a device 300, comprises a first housing 302 and a second housing304 for holding a flexible disk (shown in broken lines) therebetween.The device 300 is substantially similar to the device 200, describedabove with the first housing 302 including a lumen 306 extendingtherethrough and a surface 308 which faces a space in which a disk willbe received. The surface 308 includes a protrusion 310, which may extendaround the lumen 306 continuously or non-continuously as described abovein regard to device 200. As described above in regard to the protrusion214, the protrusion 310 has a circumference less than that of an outercircumference 312 of the first housing 302 but greater than an innercircumference 314 of the first housing 302 which forms the lumen 306.The second housing 304 includes a lumen 316 extending therethrough and asurface 318 which faces the space within which a disk will be received.The device 300 differs from the device 200, however, in that the surface318 also includes a protrusion 320 which extends either continuously ordiscontinuously about the lumen 316. A circumference of the protrusion318 is less than an outer circumference 322 of the second housing 304but greater than an inner circumference 324 of the second housing 304which forms the lumen 316. It will be understood by those of skill inthe art that the protrusion 310 of the first housing 302 preferablysubstantially aligns with the protrusion 320 of the second housing 304such that a disk held therebetween is gripped by the first and secondhousings 302, 304, respectively, with the protrusions 310 and 320pressing portions of the disk inward toward one another. Thus, theprotrusions 310, 320 form a fixation feature which holds the disktherebetween.

When the protrusions 310, 312 are aligned to hold the disk therebetween,a space 326 radially outside the protrusions 310, 320 forms a reliefwell allowing an outer portion of the disk to remain substantiallyunsecured therein to flex in either direction (i.e., toward the firsthousing 302 or toward the second housing 304) to accommodate thevibrations associated with high pressure fluid flow. A space 328 formedradially within the protrusions 310, 320 (i.e., between the protrusions310, 320 and the lumens 306, 316) allows a central portion of the disk,including the slitted portion, to flex to accommodate high pressurefluid flow. In other words, the central portion of the disk may flextoward the first housing 302 until the disk contacts the disk-facingsurface 308 and/or toward the second housing 304 until the disk contactsthe disk-facing surface 318. Thus, it will be understood by those ofskill in the art that the space 328 allows the disk to accommodate ahigh pressure fluid flow in either direction. However, it will also beunderstood by those of skill in the art, that when there is no fluidflow through the device 300, the disk need not be biased in anyparticular direction, either positive or negative.

As shown in FIGS. 7 and 8, a device 400, according to another embodimentof the present invention, comprises a first housing 402 and a secondhousing 404 for holding a flexible disk (shown in broken lines)therebetween. The first housing 402 includes a lumen 406 extendingtherethrough and a disk-facing surface 408 which includes a protrusion410 extending from the surface 408. The protrusion 410 extends aroundthe lumen 406 either continuously or non-continuously in the same mannerdescribed above radially within an outer circumference 412 of the firsthousing 402 and radially outside an inner circumference 414 of the firsthousing 402 which forms the lumen 406. An outer annular space betweenthe outer circumference 412 and the protrusion 410 forms a relief well428 while an annular space between the protrusion 410 and the innercircumference 414 forms a relief well 430. The protrusion 410 may alsoinclude a pointed tip 426, as shown in FIG. 7. The protrusion 410 mayalso be angled such that the pointed tip 426 is offset radially outwardfrom a proximal end 432 at which the protrusion 410 meets the surface408. It will be understood by those of skill in the art that the pointedtip 426 may provide an improved grip of the disk 106 over aflat-surfaces protrusion 410.

The second housing 404 includes a lumen 416 extending therethrough andforms a disk-facing surface 418 radially outside the lumen 416. Thedisk-facing surface 418 optionally includes an indentation 420 (or aseries of indentations 420 if the protrusion 410 is non-continuous)corresponding to a shape of the protrusion 410 formed on the firsthousing 402 and angled similarly thereto. Thus, portions of a diskreceived between the first and second housings 402, 404, respectively,and pinched by the protrusion(s) 410 will be pushed into theindentation(s) 420, locking the disk in position with a slittherethrough aligned with the lumens 406 and 416 while the relief wells428 and 430 allow for flexing of the disk and the accommodation ofvibrations under high pressure fluid flow. Alternatively, a device 400may include only a protrusion 410 without a corresponding indentation420 and the same modification may be made to any of the devices 400,400′ and 400″ described below.

Alternatively, a device 400′ as shown in FIG. 8 may include a protrusion410′ and a corresponding indentation 420′ (or a series of non-continuousprotrusions 410′ and indentations 420′) without the pointed tip of thedevice 400. Specifically, as shown in FIG. 8, the protrusion(s) 410′ andthe indentation(s) may be substantially rectangular in cross-section toform similar radially outer and inner relief wells 428′ and 430′,respectively. In this case, a portion of a disk received between thefirst and second housings 402′, 404′, respectively, will be pushed bythe protrusion(s) 410′ into the indentation(s) 420′, locking the disk inposition with a slit therethrough aligned with the lumens 406′ and 416′and so that the relief wells 428′ and 430′ allow for flexing of the diskand the accommodation of vibrations under high pressure fluid flow.

In a further embodiment of the device 400″ as shown in FIG. 9 isconstructed in substantially the same manner as the device 400′ exceptthat the first housing 402″ includes a second protrusion 434″ on a diskfacing surface 408″ thereof which may be either continuous ornon-continuous in the same manner described above for the protrusions ofthe previous embodiments while the second housing 404″ includes a secondindentation 436″ on a disk-facing surface 418″ thereof which maycorrespond in shape and position to the second protrusion 434″. Thedevice 400″ defines a radially outer relief well 428″ between the firstprotrusion 410 and an outer circumference 422″ of the first housing 402″and a radially inner relief well 430″ between the second protrusion 434″and the lumen 406″. It will be understood by those of skill in the artthat the first and the second housings 402, 404, respectively mayinclude any number of protrusions and indentations as desired to moresecure retain a disk gripped therebetween.

As shown in FIG. 10, a device 500, according to another embodiment ofthe present invention, comprises first and second housings 502, 504,respectively include disk facing surfaces 508, 518 respectively forholding a flexible disk therebetween. The device 500 is substantiallysimilar to the device 400, as described above except that, while thedisk-facing surface 508 includes a protrusion 510 shaped and positionedsubstantially similarly to the projection 410 shown in FIG. 7, thedisk-facing surface 518 of the second housing 504 includes nocorresponding indentation and, in this case, is substantially planarsuch that, when a flexible disk is positioned between the first andsecond portions 502, 504, respectively, with a slit thereof aligned withthe lumens 506 and 516, portions of the disk contacting theprotrusion(s) 510 are pinched against the flat surface 518 locking thedisk in position while radially outer and inner relief wells 522, 524,respectively, allow for flexing of the disk and the accommodation ofvibrations under high pressure fluid flow.

According to another exemplary embodiment shown in FIG. 11, a device 600comprises a first housing 602 and a second housing 604 for holding aflexible disk (shown in broken lines) therebetween. The first housing602 includes a lumen 606 extending therethrough and a disk-facingsurface 608. The disk-facing surface 608 includes an inner portion 610immediately surrounding the lumen 606 and an outer portion 612 extendingradially from the inner portion 610 at a distal end of the lumen 606.The outer portion 612 may be substantially planar and oriented in anydesired relationship to an axis of the lumen 606 (e.g., substantiallyperpendicular thereto). The inner portion 610 is angled such that aproximal opening 606′ of the lumen 606 is smaller than a distal opening606″ thereof. That is, in this embodiment, the lumen 606 issubstantially conical flaring outward distally.

The second housing 604 includes a lumen 614 extending therethrough to aproximal disk-facing surface 616. The lumen 614 may for example besubstantially cylindrical and approximately equal in diameter to theproximal opening 606′ of the lumen 606. The disk-facing surface 616includes a radially inner portion 618 separated from a radially outerportion 620 by a protrusion 622 which may be formed as described inregard to any of the above embodiments. The inner portion 618 is angledso that, when the first and second housings 602, 604, respectively, aremated to one another with a slitted, flexible disk gripped therebetween,it is substantially parallel to the inner portion 610 of the firsthousing 602. Furthermore, as would be understood by those skilled in theart, although distal opening 606″ is wider than the proximal opening614′, the flexible disk (shown in broken lines) will preferably have aslit which is no wider than the opening 614′ and which, when grippedbetween the first and second housings 602, 604, respectively, will beentirely radially within the opening 614′ so that fluids will pass fromthe lumen 606 to the lumen 614 without leaking along the inner portion618.

As in the above-described embodiments, the protrusion 622 extendscontinuously or non-continuously around the lumen 614 separatedtherefrom by the inner portion 618 and separated from an outercircumference 624 of the second housing 604 by an annular space forminga relief well 626. It will be understood in the art that when the firstand the second housings 602, 604, respectively, are mated together tosecure a flexible disk therebetween, the flexible disk will bend toaccommodate the angled inner portions 610, 618 with a portion of theflexible disk secured between the outer portions 612, 620 fixed to theouter portion 612 of the disk-facing surface 608 by the protrusion 622.Additionally, it will be understood by those of skill in the art that inorder to accommodate the angled inner portions 610, 618 a centralportion of the disk, including the slitted portion, bends in a proximaldirection.

As shown in FIG. 12, a device 700 according to another embodiment of theinvention comprises a first housing 702 and a second housing 704 forholding a flexible disk (shown in broken lines) therebetween. The firsthousing 702 includes a lumen 706 extending therethrough to a distalopening 706′ surrounded by a disk-facing surface 708. An inner portion710 of he disk-facing surface 708 is substantially conical, anglingproximally away from the opening 706′ to meet a substantially planarouter portion 712 extending radially outward therefrom. The secondhousing 704 includes a substantially conical lumen 714 extendingtherethrough from a proximal opening 714′ to a smaller distal opening714″. The proximal opening 714′ is surrounded by a disk-facing surface716 separated from the opening 714′ by a protrusion 722. The innerportion 718 comprises a wall immediately surrounding the lumen 714 andis shaped, for example, to correspond to the shape of the inner portion710 of the first housing 702. That is, in this embodiment, the innerportion 718 is angled such that the lumen 714 is recessed relative tothe outer portion 720. As in the previously described embodiments, theprotrusion 722 may extend continuously or non-continuously around theopening 714′ within an outer circumference 724 of the second housing 704to define a relief well 726 within which will be received a radiallyouter portion of a slitted, flexible disk to be gripped between thefirst and second housings 702, 704, respectively. As described above,the disk will be pinched between the projection 722 and the outerportion 712 and between the inner portions 710 and 718 leaving theradially outer portion of the disk free to vibrate when exposed to highflow rates.

As will be understood by those of skill in the art, the flexible diskwill bend to accommodate the angled inner portions 710, 718 of the diskfacing surfaces 708, 716 creating a positive slit bias reducing thepressure required for flow proximal to distal as compared to thatrequired for flow from the distal to the proximal.

As shown in FIG. 13, a device 800 according to another embodiment of theinvention comprises a first housing 802 and a second housing 804 forholding a flexible disk (shown in broken lines) therebetween. The firsthousing 802 includes a lumen 806 extending therethrough and adisk-facing surface 808 including a recessed portion 810 extendingaround an outer-most perimeter of the disk-facing surface 808. That is,a portion of the first housing 802 radially outside the disk-facingsurface 808 is recessed away from the second housing relative to thedisk-facing surface 808. The second housing 804 includes a lumen 812extending therethrough and a disk-facing surface 814 which includes anon-continuous or continuous protrusion 816 as described above extendingaround an outer-most perimeter of the disk-facing surface 814. Aradially inner surface of the protrusion 816 is radially further fromthe lumens 806, 812 than the outer perimeter of the disk-facing surface808 so that an annular gap extends there between when the first housing802 is coupled to the second housing 804 with a flexible disk grippedtherebetween. It will be understood by those of skill in the art thatalthough the protrusion 816 is described as formed on the disk-facingsurface 814 of the second housing 804, an o-ring may be included in thedevice 800 as an alternative to the protrusion 816. In this alternativeembodiment, the o-ring may be placed between the first and the secondhousings 802, 804 when the disk is being fixed therebetween insubstantially the same position described for the protrusion 816.

A circumference of the disk-contacting portion 818 of the disk-facingsurface 808 may be smaller than a circumference of the protrusion 816 onthe disk-facing surface 814 such that when the first and second housing802, 804 are mated, a relief well 822 is formed by an annular spacebetween an inner surface 824 of the protrusion 816 and an outer surface826 of the disk-contacting portion 818. The disk may be fixed betweenthe first and the second housings 802, 804, respectively, such that thedisk-contacting portion 818 secures the disk to a disk-contactingportion 820 of the disk-facing surface 814 radially within theprotrusion 816. It will be understood by those of skill in the art thatthe disk may be positioned therebetween such that the disk issubstantially planar or, in the alternative, such that outer edges ofthe disk are deformed, as shown in FIG. 13, by the protrusions 816.Thus, an unsecured radially outer portion of the disk may flex withinthe relief well 822 to accommodate high pressure fluid flowtherethrough. As the remaining portion of the disk is firmly securedbetween the disk-contacting portion 818 and the disk-contacting portion820, it will be understood by those of skill in the art that the aneutral slit bias exists, meaning that, in this embodiment, the device800 opens to permit flow from proximal to distal at substantially thesame threshold pressure as it opens to permit flow from distal toproximal.

As shown in FIG. 14, a device 900 according to another embodiment of theinvention comprises a first housing 902 and a second housing 904 forsecuring a flexible disk (shown in broken lines) therebetween. Thedevice 900 is substantially similar to the device 800 described aboveexcept that the first housing 902 includes a protrusion 910 extendingcontinuously or non-continuously around an outer-most perimeter of adisk-facing surface 908 as described above while the second housing 904includes a recessed portion 914 extending around an outer-most perimeterof a disk-facing surface 912, radially outside a disk-contacting portion920 of the disk-facing surface 914. Similarly to the device 800, thefirst housing 902 includes a lumen 906 extending therethrough while thesecond housing 904 includes a lumen 912 extending therethrough. Acircumference of the disk-contacting portion 920 of the disk-facingsurface 914 is smaller than a circumference of the protrusion 910 on thedisk-facing surface 908 such that, when the first and second housing902, 904, respectively, are mated to one another, a relief well 922 isformed by an annular space between an inner surface 924 of theprotrusion 910 and an outer surface 926 of the disk-contacting portion920. Thus when a disk is fixed between the first and the second housings902, 904, respectively, with the disk-contacting portion 920 securingthe disk to a disk-contacting portion 918, an outer edge of the disk isfree to flex within the relief well 922 when a high pressure fluid flowpasses therethrough. Similarly, it will be understood by those of skillin the art that although the protrusion 910 is described as formed onthe first housing 902, an o-ring may be included in the device 900 inplace of the protrusion 910 between the first and the second housings902, 904, respectively, in the same position occupied by the protrusion910.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the structure and themethodology of the present invention, without departing from the spiritor scope of the invention. For example, in any of the embodiments any ofthe features mentioned for a first housing may be moved to a secondhousing and vice versa. In addition, features mentioned with respect tocontrolling flow in the distal to proximal direction may be reversed toobtain the same effect in proximal to distal flow and vice versa. Thus,it is intended that the present invention cover any modifications thatcome within the scope of the appended claims and their equivalents.

1-22. (canceled)
 23. A valve comprising: a first housing including afirst lumen extending therethrough and a first disk-facing surface; asecond housing including a second lumen extending therethrough and asecond disk-facing surface, the second housing being coupled to thefirst housing so that the second disk-facing surface faces the firstdisk-facing surface; and a flexible disk having at least a portion of anouter edge of the disk extending away from a plane of a central portionof the disk, the outer edge contacting the first disk-facing surface,the disk including a slit extending therethrough which, when acted uponby a fluid pressure of at least a threshold level opens to permit fluidflow between the first and second lumens and which, when acted upon by afluid pressure less than the threshold level, prevents fluid flowbetween the first and second lumens;
 24. The valve of claim 23, whereinthe outer edge contacts the second disk-facing surface.
 25. The valve ofclaim 23, wherein one of the first and second disk-facing surfacesincludes a first protrusion extending therefrom toward the other of thefirst and second disc-facing surface, the first protrusion extendingaround the first and second lumens.
 26. The valve of claim 23, whereinthe first disk-facing surface lies in a recessed portion formed in thefirst housing and extending around the first lumen radially.
 27. Thevalve of claim 23, wherein the second disk-facing surface lies in arecessed portion formed in the second housing and extending around thesecond lumen radially.
 28. The valve of claim 23, wherein the firstdisk-facing surface includes a first protrusion extending therefrom. 29.The valve of claim 28, wherein the first protrusion extendssubstantially continuously around the first lumen.
 30. The valve ofclaim 28, wherein the first protrusion is one of a plurality of discreetprotrusions.
 31. The valve of claim 28, wherein the second disk-facingsurface includes a recessed portion aligned with the first protrusionsuch that when the first and second housings are mated to one another,the first protrusion is accommodated within the recessed portion. 32.The valve of claim 23, wherein at least a portion of the firstdisk-facing surface is angled relative to the longitudinal axis of thevalve.
 33. The valve of claim 32, wherein at least a portion of thesecond disk-facing is angled relative to the longitudinal axis of thevalve.
 34. The valve of claim 23, wherein the flexible disk includes aplurality of slits extending therethrough.
 35. The valve of claim 23,wherein the first housing includes a third lumen extending therethrough.36. The valve of claim 35, wherein the second housing includes a fourthlumen extending therethrough.
 37. A valve comprising: a first housingincluding a first lumen extending therethrough and a first disk-facingsurface, wherein the first disk-facing surface lies in a first recessedportion of the first housing, the first recessed portion defined atleast partially by a wall oriented substantially parallel to alongitudinal axis of the valve; a second housing including a secondlumen extending therethrough and a second disk-facing surface, thesecond housing being coupled to the first housing so that the seconddisk-facing surface faces the first disk-facing surface; and a flexibledisk, wherein at least a portion of an outer edge of the disk extendssubstantially perpendicularly away from a plane of a central portion ofthe disk, the outer edge contacting the first disk-facing surface andthe wall, the disk including a slit extending therethrough which, whenacted upon by a fluid pressure of at least a threshold level opens topermit fluid flow between the first and second lumens and which, whenacted upon by a fluid pressure less than the threshold level, preventsfluid flow between the first and second lumens.